The present invention generally relates to document retrieval systems, and more particularly to a fuzzy document retrieval system which makes a retrieval with moderate quantity and quality by displaying a result of the retrieval in a sequence dependent on the degree of matching with a retrieval condition when a user retrieves from a document database a document which matches a formula of the retrieval condition which is designated.
The present inventor has previously proposed a document retrieval system which generates a group of keywords which are close to the vocabulary or image of the user at a high speed and with a high flexibility in a U.S. patent application Ser. No. 296,769 filed Jan. 13, 1989.
On the other hand, a retrieval system which associatively retrieves an injunction corresponding to a cause based on a software common knowledge IR system by inputting keywords which are obtained from examples of faults which occur in the software development stage is proposed in Hashimoto et al., "Software Common Knowledge IR System SOCKS(1)", The 35th National Conference of the Information Processing Society, 1987 and Tsuji et al., "Software Common Knowledge IR System SOCKS(2)", The 35th National Conference of the Information Processing Society, 1987.
According to the two systems referred above, the result of the retrieval is not displayed in a binary value which indicates "YES" or "NO". These two systems are characterized in that the result of the retrieval is indicated by a value [0, 1] called relevance.
However, when realizing such systems, there is a problem in that an extremely large number of operations must be carried out on real numbers. In addition, such operations are unsuited for a general computer because the number of calculations is proportional to the number of documents.